Rear Heated Seats

Rear Heated Seats Description and Operation

Rear Heated Seat Components

The rear heated seat system has one control module that controls heat operation for both the left and right rear seat. The rear heated seats system consists of the following components:

* Rear seat heating control module

* Body control module

* Left rear seat heating switch

* Right rear seat heating switch

* Left seat cushion heating element

* Left seat back heating element

* Right seat cushion heating element

* Right seat back heating element

Power and Grounds

Battery positive voltage is supplied to the rear seat heating control module through a fuse located in the rear fuse block. This voltage is used to power up the rear seat heating control module and to supply power to the seat heater elements. Ground for the rear seat heating control module is provided at G302.

Heated Seat Operation

Ground is supplied at all times to the rear seat heating switches located in the auxiliary radio/HVAC controls. When a heated seat switch is pressed, the heated seat switch signal circuit from the BCM is pulled low indicating the heated seat command. The BCM serves as the heated seat system master to transmit the message to the rear seat heating control module via the serial data line.

When the seat heating control module receives a heated seat command, it applies high side drive pulse width modulated (PWM) signals driven at the required duty cycles to generate the appropriate effective voltage to the heating elements to attain the commanded seat temperature.

The rear seat heating system utilizes a self-regulating heating element system, which is different from the non-regulated heating element systems with temperature sensors previously used on GM vehicles. In the self-regulating type of system, temperature feedback to a control module is not required for temperature regulation. The heating element material itself regulates the surface temperature based on the effective voltage applied to the heating element.

Load Shed Management

The electrical power management function is designed to monitor the vehicle electrical load and determine when the battery is potentially in a high discharge condition. The heated/cooled seat system is one of the vehicle loads that is subject to reduction during a battery discharge condition. For more information on load management refer to Electrical Power Management Description and Operation Description and Operation.